Can you minimize a function in MATLAB?

The force is F=(mMg)/(cos(theta)+Msin(theta), and theta is between 0 and pi/2 I have the values for m, M and g but I need to find the angle that the force is the smallest. I also need to find the magnitude of the force. To find the angle where force is the smallest, do I need to minimize it? How would I go about doing that?

3 commentaires

the cyclist
the cyclist le 29 Avr 2015
Not related to your MATLAB question, but you might want to be careful with your force definition. It looks like you might have mismatched units in the denominator.
John D'Errico
John D'Errico le 29 Avr 2015
Modifié(e) : John D'Errico le 29 Avr 2015
It depends on what M means. If M has units, then, yes, there is arguably a problem, because we would have
cos(theta) + M*sin(theta)
in an additive expression. That works only if M is unit-less.
But to be honest, it looks like M might be unit-less. My guess is m is a mass, g looks like an acceleration. Therefore m*g is a force, and we have no use for units on M.
the cyclist
the cyclist le 29 Avr 2015
You are absolutely correct. I assumed that M is a large mass, and m a small mass.

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John D'Errico
John D'Errico le 29 Avr 2015
Use fminbnd. I'll show you how to define the function.
F = @(theta) (m*M*g)./(cos(theta)+M*sin(theta));

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